Forest Falls is situated in the San Bernardino Mountains of California, at elevations ranging from approximately 5,000 feet (1,500 m) to 6,000 feet (1,800 m) along the steep gradient of Mill Creek, a tributary of the Santa Ana River. It lies 75 miles (121 km) due east of the Los Angeles Civic Center, and 21 miles (34 km) from San Bernardino, the nearest large city and the county seat. The community stretches for approximately 5 miles (8.0 km) in a narrow band primarily along the south side of the linear canyon of Mill Creek, which trends slightly north of east. The highest portions of the San Bernardino Mountains, including southern California’s highest point, San Gorgonio Mountain at 11,503 feet (3,506 m), lie directly north of Forest Falls in the San Gorgonio Wilderness Area. The falls for which the community is named descend from this high area over the northern edge of the canyon of Mill Creek.